In order for the Internet-based digital products to be widely accepted, secure copyright distribution mechanism must be provided with advanced traitor tracing mechanism.We present new software copyright protection and electronic license distribution model based on public key scheme. In this model, digital contents can be distributed over a broadcast channel in a encrypted form and the authorized user can decrypt it, which can be traced back with proposed public key tracing mechanism. Proposed model provides efficiency since merchant server can issue electronic licenses in advance by preprocessing. It also provides secure and efficient software live-update mechanism based on traitor tracing scheme.1